Table Of Contents - Generac Power Systems GP Series Diagnostic And Repair Manual

Safety .......................................................................... ii
Read This Manual Thoroughly .................................... ii
Replacement Parts ..................................................... ii
Section 1 Description and Components ....................1
Introduction .................................................................1
Engine-Generator Drive System .................................1
The AC Generator ......................................................1
Rotor Assembly ..........................................................1
Stator Assembly ..........................................................1
Brush Holder and Brushes .....................................2
Other AC Generator Components ..............................2
Excitation Circuit Breaker .......................................2
Voltage Regulator ...................................................2
Adjustment Procedure
(12.5 kW and Older 15 kW Units) ............................3
Adjustment Procedure
(Newer 15 kW and All 17.5 kW Units) .....................3
Circuit Breakers ......................................................3
Rotor Residual Magnetism .........................................3
Field Boost Circuit .......................................................3
Operation ....................................................................4
Startup ....................................................................4
On-Speed Operation ..............................................4
Field Excitation .......................................................4
AC Power Winding Output ......................................4
Battery Charge Winding Output ..............................4
10 Amp Battery Charge Winding Output ................4
Specifications ..............................................................5
Section 2 Engine DC Control System ........................7
Printed Circuit Board ...................................................7
General Theory .......................................................7
Circuit Board Connections ......................................7
Dip Switch Positions ...............................................7
Battery ........................................................................7
Recommended Battery ...........................................7
Control Panel Component Identification .....................8
Operational Analysis (Older Units) ...........................10
Circuit Condition - Rest .........................................10
Circuit Condition - Start ........................................12
Circuit Condition - Run .........................................14
Circuit Condition - Stop .........................................16
Fault Shutdown .....................................................17
Operational Analysis (Newer Units) ..........................18
Circuit Condition - Rest .........................................18
Circuit Condition - Start ........................................20
Circuit Condition - Run .........................................22
Circuit Condition - Stop .........................................24
Fault Shutdown .....................................................24
Diagnostic Repair Manual

Table of Contents

Section 3 Troubleshooting Flowcharts ....................27
Introduction ...............................................................27
Section 4 AC Diagnostic Tests .................................35
Introduction ...............................................................35
Safety .......................................................................35
Important Note Concerning Connectors ...................35
Test 1 - Check No-Load Voltage and Frequency ....35
Test 2 - Check Main Circuit Breaker ........................36
Test 3 - Test Excitation Circuit Breaker ...................36
Test 4 - Fixed Excitation Test/Rotor Amp Draw Test 36
Test 5 - Check Stepper Motor Control .....................38
Test 6 - Wire Continuity ...........................................39
Test 7 - Check Field Boost ......................................40
Test 8 - Diode/Resistor ............................................40
Test 9 - Test Stator ..................................................41
Test 10 - Sensing Leads ..........................................42
Test 11 - Excitation Wiring .......................................43
Test 12 - Check Brush Leads ..................................43
Test 13 - Check Brushes & Slip Rings .....................44
Test 14 - Check Rotor Assembly .............................44
Test 15 - Check Load Voltage & Frequency ............45
Test 16 - Check Load Watts and Amperage ............45
Test 17 - Check Battery Charge Output ..................45
Test 18 - Check 10 Amp Battery Charge Output .....45
Test 19 - Check Battery Charge Rectifier (BCR2) ...46
Test 20 - Check 10 Amp Circuit Breaker .................46
Test 21 - Check 10 Amp Fuse .................................47
Test 22 - Check Battery and Cables ........................47
Test 23 - Check Voltage At Starter Contactor (SC) .48
Test 24 - Check Starter Contactor (SC) ...................48
Test 25 - Check Starter Motor .................................48
Test 26 - Test Starter Contactor Relay (SCR) .........49
Test 27 - Check Start-Run-Stop Switch (SW1) ........50
Test 28 - Check Start-Run-Stop Switch (SW1) Wiring .50
Test 29 - Check Ignition Spark ................................50
Test 30 - Check Spark Plugs ...................................51
Test 31 - Remove Wire 18 / Shutdown Lead ...........51
Test 32 - Test Start Stop Relay (SSR) .....................51
Test 33 - Test Wire 167 ...........................................52
Test 34 - Test Start Stop Relay Wiring ....................53
Test 35 - Check and Adjust Ignition Magnetos ........54
Test 36 - Test Fuel Shutoff Solenoid (FSS) .............55
Test 37 -Test Fuel Shutoff Solenoid Voltage ...........55
Test 38 - Check Fuel Pump .....................................55
Test 39 - Check Carburetion ....................................55
Test 40 - Valve Adjustment ......................................56
Test 41 - Check Engine / Cylinder Leak
Down Test / Compression Test ................................57
Test 42 - Check Oil Pressure Switch and Wire 86 ...58
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